The present invention relates to a binocular, and more particularly, to a binocular including a compact optical arrangement structure for varying magnification.
Some binoculars include xe2x80x9czoomingxe2x80x9d mechanisms capable of continuously varying magnification.
During zooming, some of the optical systems in the two telescope systems that form the binocular include two or more lenses for varying magnification. The lenses are moved along respective optical axes of the two binocular systems to different positions by means of a zooming adjustment structure. The magnification lenses are sometimes included in the eyepiece optical system, and change the focal lengths of the eyepiece optical system, thereby continuously varying the magnification
In some conventional zooming mechanisms, cam mechanisms for driving the moving magnification lenses are provided in each of right and left lens barrels, and cooperate with each other by means of a driving mechanism driven by (for example) a gear box.
However, the conventional zooming mechanism for a binocular occupies a significant amount of space, so that it is difficult to efficiently accommodate the mechanism in a small size binocular. That is, a conventional zooming adjustment mechanism occupies enough space so that it is difficult to make a smaller zooming binocular. Accordingly, zooming binoculars tend to be larger than a compact format, e.g., larger than a compact binocular that may fit in a pocket or similar size.
It is therefore an object of the invention to reduce the size of a binocular by reducing a space occupied by an optical arrangement unit that moves the magnification varying lenses of the right and left telescope optical systems.
A binocular according to an embodiment of the invention includes an outer body housing, right and left lens barrels, and right and left telescope optical systems accommodated respectively in the right and left lens barrels. A plurality of movable optical systems, provided in a portion of the telescope optical systems, are movable along an optical axis direction upon different moving conditions so that a magnification of an observed image observed through the telescope optical systems is varied and/or so that a focal distance of the image is changed.
A first movable optical system and a second movable optical system are included in each the plurality of movable optical systems. A first guiding member guides and moves the first movable optical system of each of right and left telescope optical systems, along the optical axis direction with a same respective right and left distance. A second guiding member guides and moving the second movable optical system of each of right and left telescope optical systems, along the optical axis direction with a same respective right and left distance. An arrangement structure operates for moving the first and second movement member along the optical axis direction upon different moving conditions. The arrangement structure is disposed between the right and left lens barrels, and a supporting plate is disposed above or below the right and left telescope optical systems with a predetermined space provided therefrom, the supporting plate extending both in the optical axis direction and in the lateral direction. The first and second guiding members are disposed and moved inside the space.
Optionally, the right and left lens barrels are moved symmetrically with respect to a lateral direction center line of the supporting plate in the right and left direction thereof.
Further, the first movement member may include a first arm member formed of a pair of right and left arms, respectively extending rightward and leftward, for engaging with the right and left first moving optical systems. In this case, the second movement member has a second arm member formed of a pair of right and left arms, respectively extending rightward and leftward for engaging with the right and left second moving optical systems.
Still further optionally, the first and second arms are parallel to each other inside the space and are approximately flush with each other, portions of the first and second guiding members being flush with each other, and the first and second arms are constituted to move along the optical axis direction upon different moving conditions so as not to interfere with each other.
Optionally, the arrangement structure is provided with a body disposed in a center portion along the right and left directions of the binocular, the body being provided with first and second connecting members formed for respectively connecting with the first and second guiding members. The first guiding member includes a first center member between the first arms, the first center member connecting to the first connecting member, and the second guiding member includes a second center member between the second arms, the second center member connecting to the second connecting member. The first and second connecting members move along the optical axis direction upon different moving conditions.
Further, the arrangement structure includes a guide, the first and second center members respectively have guided members that are guided by the guide for slidably moving along the optical axis direction.
Still further, the first arm member is constituted in such a manner that each distance between the right and left guided members of the first arm member and right and left connecting portions that connect to the first moving optical systems respectively are equal to each other.
Additionally, the second arm member is constituted in such a manner that each distance between the right and left guided members of the second arm member and right and left connecting portions that connect to the second moving optical systems respectively are equal to each other.
Optionally, the first moving optical system is connected to the first arm member in such a manner that the first moving optical system is movable laterally along the longitudinal direction of the first arm member, and the second moving optical system is connected to the second arm member in such a manner that the second moving optical system is movable laterally along the longitudinal direction of the second arm member.